My issue with Thorgrim is that from what I recall, he was something of a father figure to Belegar. He encouraged Belegar to set of the Expedition to take K8P, gave him supplies and encouragement and money, and sent him off. And when Belegar returned having taken 3 peaks, thinking, "Yeah... yeah, I can do this thing! I might be able to make this work!" what was Thorgrim's response?
"How long can your foothold last? Long enough to take some vengeance? Strike out some grudges?" Thorgrim never believed in Belegar, not for a moment. It was all about striking out some grudges.
Mind you, this is a case of, "Thorgrim told you what he was." He was the High King who announced an Age of Vengeance. He was the one who decided that the dawi are doomed and all that mattered was striking out every last grudge. Belegar should have known... but he didn't. Somehow Belegar managed to get the idea that Thorgrim believed in him.
"How long can your foothold last?" Man. I think that was maybe the cruelest line in the entire quest. Oh, characters have done far worse things, but never before or since have we seen someone so close to another person say words quite so crushing.